1. Field of the Invention
The present invention relates generally to a method of humanely euthanizing animals.
2. Description of the Related Art
The subject of euthanasia in the biomedical research industry is not an easy one. Debates occur as to which are the preferred methods and reasons for euthanasia. New standards have been set by the Canadian Council on Animal Care (C.C.A.C.) requiring anesthesia before carbon dioxide. Debates continue within the industry and compliance to the new regulation may require more strict-enforcement.
Various methods for euthanizing animals are known in the art, including, for example, physical methods in the form of stunning, cervical dislocation, electrocution, pithing, decapitation, shooting, maceration, microwave radiation and exsanguinations. One may also use non-inhalant pharmacological agents, inhalant anesthetics or non-anesthetic gases.
In determining the type of euthanizing process to use, individuals are urged to consider the humaneness and pain involved in the process, despite the inevitable demise of the animal. As such, a set of criteria have been set forth to be used when determining what process of euthanasia to use. The criteria include: (1) ability to induce loss of consciousness and death without causing pain, distress, anxiety, or apprehension; (2) time required to induce loss of consciousness; (3) reliability; (4) safety of personnel; (5) irreversibility; (6) compatibility with requirement and purpose; (7) Compatibility with subsequent evaluation, examination, or use of tissue; (8) drug availability and human abuse potential; (9) compatibility with species, age, and health status; (10) ability to maintain equipment in proper working order; and (11) safety for predators and scavengers should the carcass be consumed.
When considering the criteria, many experts find that on the whole, exposure of carbon dioxide gas to the animal is one of the more humane means euthanizing the animal. However, many research papers discussing this topic also identify a high level of distress that is prevalent with euthanasia using carbon dioxide alone, as a result of the tests Canada now requires the use of an anesthesia before the introduction of carbon dioxide.
Carbon dioxide is the preferred method of euthanizing small animals and rodents because it is a relatively inexpensive gas that is colorless and odorless at low concentrations. Carbon dioxide is also considered to be quickly and readily taken into the body. Narcotic effects of CO.sub.2 are well known, but the burning of the eyes, lungs and nasal passages due to carbolic acid make it inhumane. By introducing an anesthetic to small animals such as Isoflurane before introducing carbon dioxide the animals are euthanized in the most humane way possible.
Presently, other euthanasia processes involving carbon dioxide gas as the means of euthanizing small animals such as rodents, have carbon dioxide introduced to cause death by suffocation. Such processes of introducing carbon dioxide that is not preceded by anesthesia tend to dramatically increase the stresses upon the animal and thereby make its impending death less humane and more painful. For example, studies have shown that too low of concentration of carbon dioxide is considered a potent respiratory stimulant resulting in a tenfold increase in the ventilation rate and a feeling of profound respiratory distress.
What is desired is a means of euthanizing one or more animals using liquid anesthetic such as Isoflurane to anesthetize the animals followed by carbon dioxide so as to substantially limit the physical stresses that are placed upon the one or more animals when conventionally euthanizing with only carbon dioxide.